Trenching tooth and method

ABSTRACT

A molded trenching tooth has a bracket (A) for attachment to a driven trenching member and carries a body having an outwardly inclined lower portion (B) and inwardly extending upper portion (C) that are joined by a curved intermediate portion integrally connecting the body members. A forward edge (D) is provided for facilitating entry of the tooth into the earth while at least one additional groove (E) in the body is aligned with the forward edge (D) providing a next successive edge of a new tooth formed thereby when the forward edge of the body wears away.

[0001] This invention relates to a self sharpening trenching tooth and method wherein the tooth is molded and is provided with a series of edges for facilitating entry into the earth whereby upon an edge being worn away, a next edge is exposed for use.

BACKGROUND OF THE INVENTION

[0002] The prior art utilizes teeth having tapered front edges and attached to a driven trenching member. A type of trencher attachment in general use is provided in the Ditch Witch RT 115 Tractor supplied by The Charles Machines Works, Inc., of Perry, Okla. Several competitive devices are on the market wherein each utilizes similar trenching teeth projecting from a driven trenching member that includes a chain supporting the teeth for entry into the earth. The trenching teeth are attached to upright tooth supports on the driven trenching member by a pair of self-locking bolts that pass through the supports and the brackets for securement at the base of the teeth. The teeth assume a generally plow shaped configuration wherein a forward edge is tapered providing a generally sharpened edge to facilitate entry of the teeth into the earth. The plow shaped body portions of the teeth incline first outwardly and are integrally joined to a generally inwardly inclined upper body portions by a curved intermediate extension.

[0003] The teeth of the prior art are constructed by cutting and bending steel plates and grinding a taper at a forward edge. Since the material from which the teeth are constructed wear rapidly because of the abrasive action of the earth, they must be exchanged often for new teeth. This results in not only loss of the teeth, machine down time, and loss of revenue but also the self locking bolts that fasten the teeth to the driven trenching member since the bolts are only capable of a single use.

[0004] Thus, the teeth and the fastening bolts constitute an expensive accessory to the trenching apparatus. The machine downtime and labor involved in removing worn teeth and installing new teeth represents a considerable expense as does the labor costs in manufacturing the teeth.

SUMMARY OF THE INVENTION

[0005] Accordingly, it is an important object of the invention to provide trenching teeth that are self sharpening so as to postpone the necessity for installing new teeth by increasing the useful life of the teeth.

[0006] Another object of the invention is to provide a molded tooth constructed from material having a higher Brinell hardness number than that of the customary bendable sheet metal from which the prior art teeth are constructed thereby reducing wear further increasing the life of teeth constructed in accordance with the invention.

[0007] Another important object of the invention is to provide a a thickened trenching tooth thereby adding strength and wear resistance minimizing the necessity for replacing worn teeth.

[0008] Another important object of the invention is to provide a trenching tooth having one or more slots aligned with the leading edges of the teeth so that as the teeth are worn away, a next succeeding leading edge is exposed so as to create what in effect is a new tooth.

[0009] Still another important object of the invention is to strengthen the teeth constructed in accordance herewith by providing at least one bridging member between respective slots.

[0010] Teeth constructed in accordance with the invention require less frequent exchanges for new teeth thereby reducing downtime as well as labor costs that are involved when installing teeth constructed in accordance to the prior art. Savings are also realized in manufacturing teeth in accordance with the invention wherein the molded construction avoids costs in fabricating and machining new teeth as well the costs of accessories such as the self locking bolts used in multiple changes of the teeth.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The construction designed to carry out the invention will be hereinafter described, together with other features thereof.

[0012] The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown and wherein:

[0013]FIG. 1 is a perspective view illustrating a movable boom for carrying a driven trenching member constructed in accordance with the prior art that includes a chain and a forward sprocket for facilitating the provision of a horizontal run of the chain during trenching;

[0014]FIG. 2 is an enlarged perspective view further illustrating teeth constructed in accordance with the prior art and the mode of attaching the teeth to a driven trenching member that includes spaced upright support members having holes therein to accommodate self-locking bolts for attaching a lower bracket portion of the teeth to the chain;

[0015]FIG. 3 is a perspective view illustrating a tooth constructed in accordance with the invention attached to a driven trenching member in the form of a driven chain as carried by the boom of a trenching apparatus with attachment of a bracket or lower base supporting member to the upright support members spaced upon the driven chain;

[0016]FIG. 4 is a side elevation looking toward an inside of a tooth constructed in accordance with the invention illustrating a pair of spaced, vertical slots in alignment with a forward edge, and with holes for fastening the teeth to the upright support members;

[0017]FIG. 5 is a sectional elevational view taken on the line 5-5 in FIG. 4 illustrating a tapered forward edges of succeeding teeth formed by the addition of the upright slots;

[0018]FIG. 6 is a sectional plan view taken on the line 6-6 in FIG. 4;

[0019]FIG. 7 is a side elevational view illustrating a modified form of the invention looking toward an inside of a tooth constructed in accordance with the invention wherein bridging members are provided at intermediate portion of the upright slots to provide rigidity and enhance the wear characteristics of the teeth;

[0020]FIG. 8 is a plan view taken on the line 8-8 in FIG. 7 illustrating the forward edges of the additional teeth and the bridging members; and

[0021]FIG. 9 is a sectional front view taken on the line 9-9 in FIG. 7 further illustrating the bridging member spanning the upright slots.

DESCRIPTION OF A PREFERRED EMBODIMENT

[0022] The drawings illustrate a tooth for a trenching tool positionable to project from a driven trenching member for entry into the earth including a bracket A attachable to the driven trenching member. A body having an outwardly inclined lower portion B is carried by the bracket integrally therewith, and an inwardly extending upper portion C is carried integrally by the lower portion. A forward edge D for facilitating entry of the tooth into the earth is carried on the body. At least one groove E in the body in a forward portion in alignment with the forward edge forms an additional forward edge defining an additional tooth when the first mentioned forward edge is worn away by the abrasive action of the earth during trenching. Thus, the useful life of the tooth is enhanced when the first mentioned forwarded edge is worn away so as to expose an additional forward edge to the earth to again facilitate entry of the tooth into the earth.

[0023] Referring more particularly to the prior art as illustrated in FIGS. 1 and 2, it will be observed that spaced trenching teeth project outwardly from a driven trenching members that includes a chain 10 provided with suitable mounting plates 11 attached thereto. The chain passes over a sprocket 12 carried at forward end of a boom 13 providing a horizontal run of the chain exposing a forward tapered tooth edges 14 to dig into the earth. The teeth are fastened to the upright support plates 11 by a pair of spaced self-locking bolts 15. As best shown in FIG. 2, a lower bracket portion 16 of the teeth provided for receiving the bolts 15 project therefrom and define an outwardly tapering portion 17 joining an intermediate curved portion 18 for carrying an inwardly inclined upper body portion 19. The upper edge 20 tapers downwardly from the front edge 14.

[0024] Referring now more particularly to FIGS. 3-6, a tooth constructed in accordance with the invention has a bracket portion A attached to the upright supporting members 11 as by self locking bolts 15 that pass through spaced holes 21 in the bracket portion A. The upright slots E are illustrated in FIGS. 4, 5, and 6 having tapering forward edges as at 22 and 23. It is these edges that are exposed for use when the forward tapering edge D and related body parts are worn away to expose successive front edges 22 and 23. The upper edge 24 is substantially flat, or at least, is not tapered downwardly to the degree of taper in prior art teeth. FIG. 5 illustrates a tapered forward edge 23 exposed by wearing away to afford what is essentially a new tooth. The components B and C are integrally joined by a curved intermediate member 27.

[0025]FIG. 6 illustrates a space 25 defining a forward portion of the vertical slots E.

[0026] FIGS. 7-9 disclose a modified form of the invention wherein the vertical slots E are provided with bridging members 26 to enhance the stability and wearing qualities of the teeth. The body components B and C are joined integrally by a curved component 27 as illustrated.

[0027] While a preferred embodiment of the invention has been described using specific terms for the several structural components, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made in the teeth and in the trenching member without departing from the spirit or scope of the following claims. 

What is claimed is:
 1. A tooth for use in a trenching apparatus positionable to project from a driven trenching member for entry into the earth comprising: a bracket attachable to the driven trenching member; a body having an outwardly inclined lower portion carried by the bracket integrally therewith, and an inwardly inclined upper portion carried integrally by the lower portion; a forward edge facilitating entry of the tooth into the earth carried on a forward portion of said body; and at least one groove in the body in alignment with the forward edge for forming an additional forward edge defining an additional tooth exposed after the first mentioned forward portion of said body is worn away by the abrasive action of the earth during trenching; whereby the useful life of the tooth is enlarged after the forward portion of said body is worn away so as to expose the additional forward edge to the earth to again facilitate entry of the tooth into the earth.
 2. The tooth set forth in claim 1 constructed of molded material having a hardness exceeding that of sheet steel capable of bending and machining.
 3. The tooth set forth in claim 1 wherein a groove in the body is provided in a forward portion of said body in alignment with the forward edge providing an additional forward edge.
 4. The tooth set forth in claim 3 wherein a plurality of grooves are provided in the body with each including tapered forward edges.
 5. The tooth set forth in claim 4 wherein a bridge member is located between the grooves for providing additional stability.
 6. A tooth for use in a trenching apparatus positionable to project from a driven trenching member for entry into the earth comprising: a bracket attachable to the driven trenching member; a body having an offset intermediate portion carried by the bracket integrally therewith; a forward edge facilitating entry of the tooth into the earth carried on said body; and at least one groove in the body in general alignment with the forward edge for forming an additional forward edge defining an additional tooth exposed after the first mentioned forward edge is worn away by the abrasive action of the earth during trenching; whereby the useful life of the tooth is enhanced after the first mentioned forward edge is worn away so as to expose the additional forward edge to the earth to again facilitate entry of the tooth into the earth.
 7. The tooth set forth in claim 6 being of thickened molded construction.
 8. The tooth set forth in claim 7 including a plurality of grooves in the body in general alignment with the forward edge having a transverse bridging member at an intermediate portion of the grooves.
 9. A method of trenching utilizing a tooth positionable to project from a driven trenching member for entry into the earth comprising the steps of: molding a bracket for the tooth attachable to the driven trenching member; molding a body having an outwardly inclined lower portion carried by the bracket integrally therewith, and an inwardly inclined upper portion carried integrally by the lower portion; molding a tapered forward edge facilitating entry of the tooth into the earth carried on said body; molding at least one groove in the body in alignment with the forward edge for forming an additional forward edge defining an additional tooth exposed after the first mentioned forward edge is worn away by the abrasive action of the earth during trenching; whereby the useful life of the tooth is enhanced requiring a lesser number of tooth changes affording savings of labor, downtime, and fasteners for the attaching bracket, after the first mentioned forwarded edge is worn away so as to expose the additional forward edge to the earth to again facilitate entry of the tooth into the earth.
 10. The method of trenching set forth in claim 9 including the step of molding a tapered forward edge on a forward edge of the tooth and upon an additional tooth.
 11. The method of trenching set forth in claim 10 including the step of molding a transverse bridge across an intermediate portion of said grooves. 